Shedding light on toxicity of SARS-CoV-2 peptides in aquatic biota: A study involving neotropical mosquito larvae (Diptera: Culicidae)

Abstract

Knowledge about how the COVID-19 pandemic can affect aquatic wildlife is still extremely limited, and no effect of SARS-CoV-2 or its structural constituents on invertebrate models has been reported so far. Thus, we investigated the presence of the 2019-new coronavirus in different urban wastewater samples and, later, evaluated the behavioral and biochemical effects of the exposure of Culex quinquefasciatus larvae to two SARS-CoV-2 spike protein peptides (PSPD-2002 and PSPD-2003) synthesized in our laboratory. Initially, our results show the contamination of wastewater by the new coronavirus, via RT-qPCR on the viral N1 gene. On the other hand, our study shows that short-term exposure (48 h) to a low concentration (40 μg/L) of the synthesized peptides induced changes in the locomotor and the olfactory-driven behavior of the C. quinquefascitus larvae, which were associated with increased production of ROS and AChE activity (cholinesterase effect). To our knowledge, this is the first study that reports the indirect effects of the COVID-19 pandemic on the larval phase of a freshwater invertebrate species. The results raise concerns at the ecological level where the observed biological effects may lead to drastic consequences.

Shedding light on the toxicity of SARS-CoV-2-derived peptide in non-target COVID-19 organisms: A study involving inbred and outbred mice

“…In our study, in particular, the hypothesis of the anticholinesterase effect observed in the brain of animals is a consequence of direct interactions between the PSPD-2002 and AChE is supported by molecular docking analysis ( Fig. 6 ), different from the findings of Charlie-Silva et al (2021) , Mendonça-Gomes et al (2021) and Malafaia et al (2022) , in which opposite effect (cholinesterasic stimulation) was observed in P. cuvieri tadpole, C. quinquefasciatus larvae and P. reticulata juveniles, respectively. In these studies, two possible mechanisms have been proposed for an increase in AChE activity.…”

“…Initially, our data pointed to the absence of induction of hyper-/hypoactivity or anxiogenic-/anxiety-like behavior by exposure to PSPD-2002, which departs from the reported effects for C. quinquefasciatus larvae and P. reticulata juveniles exposed to the same peptides. In insects, aquatic exposure to PSPD-2002 (at 40 μg/L), for 48 h, induced a significant increase in the locomotor activity of larvae ( Mendonça-Gomes et al, 2021 ), and in fish, we demonstrated that although habituation learning has not been altered by the peptides (40 μg/L, 35 days exposure), the animals exposed exhibited anxiety-like behavior ( Malafaia et al, 2022 ). At the time, we evidenced a close relationship between the stimulation of the cholinergic system in animals exposed to peptides and the induction of reported behavioral changes, which was not observed in our study.…”

“…Studies such as those of De-Lima et al (2005) , Tang et al (2013) , Mamiya et al (2013) and Pondugula et al (2021) ), by demonstrating a strong association between the occurrence of LPO in the hippocampus of rodents (who received different substances/chemical compounds) and a memory deficit in NORT, reinforce this hypothesis. However, interestingly, the increase in TBARs levels in animals exposed to PSPD-2002 does not seem to be related to the induction of oxidative stress in the brain of mice, as observed in other animals exposed to the same peptides ( Charlie-Silva et al, 2021 ; Mendonça-Gomes et al, 2021 ; Malafaia et al, 2022 ; Gonçalves et al, 2022), since the levels of hydrogen peroxide and ROS did not differ between the "control C57Bl/6 J" and "PSPD-2002 C57Bl/6 J" groups ( Fig. 4 B-C, respectively).…”

“…These studies raise not only the possibility of river resources acting as secondary sources of transmission of the disease among individuals ( Liu et al, 2020 , Giacobbo et al, 2021 , Thakur et al, 2021 ), as well as warn about the potential threat of the dispersion of the new coronavirus or its fragments to the biota ( Charlie-Silva & Malafaia, 2022 ). On this aspect, our research group recently reported some negative effects arising from the exposure of amphibians, fish, and insects to distinct protein fragments of the Spike protein of SARS-CoV-2 (Malafaia et al, 2021; Mendonça-Gomes et al, 2021 ; Charlie-Silva et al, 2021 ; Gonçalves et al, 2022; Fernandes et al, 2021 ). In Physalaemus cuvieri tadpoles, the increase in several biomarkers predictive of oxidative stress and the alteration in acetylcholinesterase (AChE) activity demonstrated that the short exposure (24 h) to these protein fragments was sufficient to affect the health of tadpoles ( Charlie-Silva et al, 2021 ).…”

“…In Physalaemus cuvieri tadpoles, the increase in several biomarkers predictive of oxidative stress and the alteration in acetylcholinesterase (AChE) activity demonstrated that the short exposure (24 h) to these protein fragments was sufficient to affect the health of tadpoles ( Charlie-Silva et al, 2021 ). In Mendonça-Gomes et al (2021) ), we showed that short-term exposure de Culex quinquefascitus larvae to protein fragments of the Spike protein of SARS-CoV-2 induced alterations in the locomotor system and in the olfactory behavior, which were associated with increased production of reactive oxygen species (ROS) and AChE activity. In addition, exposure to these fragments alter the behavior of fish ( Poecilia reticulata ), induce redox imbalance, affect the growth and development of these animals (Malafaia et al, 2021) and induce genomic instability and DNA damage (Gonçalves et al, 2022), as well as several morphological alterations in zebrafish (Danio rerio ) ( Fernandes et al, 2021 ).…”